Remote control system



July 12, 1932. H. E. ALLEN 1,867,395

REMOTE CONTROL SYSTEM Filed May 31. 1927 3 Sheets-Sheet 1 77 l I Fig-I.

Inventor: Hugh E .Allen, y M ztzwr.

July 12, 1932. H E ALLEN- 1,867,395

REMOTE CONTROL SYSTEM Filed may 51, 1927 5 Sheets-Sheet 2 Tnvennor: 4 Hugh E. Allen,

I07 His Abnorne July 12, 1932. H. E. ALLEN I REMOTE CONTROL SYSTEM Filed May 31, 1927 5 Sheets-Sheet 5 AAAAA AAA In venndr Hugh E.

Allen, y His AtLLOTTWQH.

Patented July 12, 1932 UNITED STATES HUGH E. ALLEN, OF SOOTIA, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK REMOTE CONTROL SYSTEM Application filed May 31,

My invention relates to remote control systems and more particularly to systems for performing functions, such as switching, signaling operations, etc., at remote points by means of carrier currents superposed upon conductors which are utilized for other purposesthan remote control. Such conductors, for example, may comprise those of the usual power distribution network.

One of the objects of my invention is to provide a system such that the remote function may be performed by means of a minimum number of operations on the part of the operator.

Another object of my invention is to provide a means whereby the carrier current transmitter may be energized, selectively connected to the proper feeder, or conductors over which the remote function is to be effected, keyed in accordance with the function to be performed and then disconnected from said feeder and deenergized responsively to a minimum number of operations on the part of the operator.

Another object of my invention is to provide means for indicating the function for which the transmitter has been operated to perform.

Another object of my invention is to provide a receiving system which is adapted to efiiciently perform the desired function re sponsively to carrier current impulses transmitted over the distribution conductors and which is substantially unaffected by line conditions such as surges, changing impedance, etc. on the distribution conductors.

Another purpose of my invention is to provide a system of the type indicated which may be energized throughout by means of alternating currents of commercial frequencies. 1

Still another object of my invention is to provide a system of the type indicated which may be economically constructed, which is reliable in its operation and which may be installed and operated by inexperienced and unskilled persons.

The novel features which. I believe to be characteristic of my invention are set forth with particularity in the appended claims.

1927. Serial No. 195,388.

The invention itself, however, both as to its organization and method of operation, together with further objects and advantages thereof, will best be understood by reference to the following description taken in connection with the accompanying drawings in which Fig. 1 illustrates a transmitter, and control circuits therefor which comprise a part of my invention; Figs. 2 and 3 represent details; Figs. 4 and 5 represent modifications of the circuit shown in Fig. 1; Fig. 6 illustrates a receiving circuit which comprises a part of my invention and Fig. 7 shows a relay which is utilized therewith.

Referring first to Fig. 1, 1 represents an oscillation generator or transmitter in which Y are employed electron discharge devices 2, which are energized from secondary windings 3 and 4 of transformer 5, the primary of which is adapted to be connected to an alternating current source 6 through a circuit comprising the left-hand member of switch 13, conductors 7, 8, primary windings of transformer 5, conductors 9, 10, switch 11, conductor 12 and right-hand member switch 13 back to the opposite side of the source 6. 14 indicates the usual oscillatory circuit associated with the electron discharge devices 2 and across which is connected the primary winding 15 of the output transformer 16. 17, 18 and 19 represent circuits leading to conductors over which the carrier currents are to be transmitted. These conductors may comprise the different feeder circuits of the usual power distribution system, each of the circuits 17, 18 and 19 being connected to a different feeder of the system. Each of the circuits 17 18 and- 19 are adapted to be connected by means of switches 20, 21 and 22 to the secondary winding of the output transformer 16 which is associated with the transmitter through a common conductor, 23 and conductors 17 18 and 19' respectively, the common conductor being connected between one terminal of the output transformer 16 andthe lower movable contact member of each of the switches 20,21 and 22 and the conductors 17 ,18 and 19' being connected to variable taps upon the secondary winding of the transformer 16 and to the upper mov- 109 able contact member of the switches 20, 21'

and 22 respectively. For example the circuit from the output of the transmitter to a particular feeder A comprises the common conductor 23, lower movable contact member and lower stationary contact member of switch 20 through the usual tuning inductance 58 and coupling condenser 59 to one side of the feeder circuit A, thence from the other side of the feeder circuit A through coupling condenser 60, upper stationary contact member and upper movable contact member of switch 20, conductor 17 and secondary winding of transformer 16 to the common conductor 23. Likewise the circuits leading to the other feeder circuits B and C may be traced through switches 21 and 22 and conductors 18' and 19' respectively. Variable taps are provided upon the secondary winding of the transformer 16 for the purpose of enabling proper carrier current voltages to be impressed upon different feeder circuits of the distribution system and for matching the impedance of the transmitter with that of any particular feeder.

While I have illustrated the transmitter 1 as consisting of a simple vacuum tube oscil-. lation generator energized from an alternating current source it will, of course, be understood that any desired type of transmitter may be employed, the one shown being preferred largely due to convenience and economy in associating it with the usual power distribution systems from which energizing currents of commercial frequency may be obtained. A particular advantage of the transmitter shown lies in the manner of associating the output circuits with the oscillatory circuit, the primary winding of output transformer 15 being electrically connected across the oscillatory circuit 14 as distinct from circuits in which the output circuit is inductively connected to the oscillatory circuit of the transmitter. By making transformer 16 of the high impedance type the varying impedance of the feeders to which the transmitter is connected at any particular time may be prevented from affectin the tuning of the oscillating circuit 14 and t ereby varying the frequency of the transmitter.

24 and 25 represent control devices by means of which connecting devices'are actuated to connect the carrier current transmitter 1 to the proper feeder and to a source of energy, for keying said transmitter, and for again disconnecting it from the selected feeder and the source of energy in response to a single operation on the part of the op erator, all as will later be explained. Since the remote function to be effected by means of my invention will largely be accomplished through the medium of electric switches which are moved either to the open or closed position responsively to carrier impulses transmitted over the feeder circuits, 1 have provided a control device 24 which will be utilized for actuating the desired switches to their closed position and a separate control device 25 for actuating corresponding switches to their open position. While the operation of these devices will later be explained in connection with Fig. 3 it may now be stated that the contacts associated with conductors 57, 61, 62 and 63 are connected through conductors 57 and 7, lefthand member of switch 13 to one side of the source 6. Conductors 51, 52, 53 of control device 24 lead to coding devices one of which is provided for each switch or class of switches which is adapted to be operated to its closed position responsivelyto a particular code. Conductors 54, 55, 56 on device 25 lead to correspondingvcoding devices for actuating these same switches to their open position. Conductor 64 leads to control switches for actuating connecting devices to connect the transmitter to the feeders and to a source of energy and for again disconnecting them after the coding devices have been actuated. Conductors 66 and 67 are associated with control switches for energizing indicator actuating devices as will later be explained.

26, 27 and 28 represent'indicating means each corresponding to a remote switch which is to be actuated and each of which is provided with actuating means comprising the switches 29, 30 and 31 and energizing coils 43, 44 and 45 therefor. Each of these indicating means in its preferred construction comprise two lamps either of which may be connected to an energy source by means of switches 29, 30 and 31. These switches are of the usual two position type and are adapted, when actuated in one position to connect a corresponding lamp to the energy source and to remain in that position until actuated to the opposite position where it will remain connecting the opposite indicating lamp to the energysource. The circuits by means of which the lamps ofindicating device 26 are energized may be traced from one side of the energy source 6 throu h the left-hand contact member of the switch 13, conductor 7, conductor 32, upper lamp of the indicating device 26, switch blade 29, conductor 34, conductor 35, conductor 12, right-hand contact of the switch 13 to the opposite side of the source 6. Thus with the switch member 29 in the position shown, the upper lamp of the 26 will be lighted thereby indicating that the corresponding switch'has been opened. Thus I provide indicating means 26,27 and 28 corresponding to each remote device which is to be operated from the particular transmitting equipment and a lamp in each ind1c ating device for indicating the manner in which the remote device was last operated. The actuating coils 43, 44 and 45 of these indicating devicesare energized through circuits as is shown in Fig. 2, having bridging members are provided for closing the circuits connected to the plug switches 36, 37 and 38, one of said plug members being provided with each transmitting equipment. By means of the switches 36, 37 and 38, which I prefer to term selecting switches, I am enabled to selectively establish the circuits through the energizing coils 39, 41 and 42 of the connecting switches 20, 21 and 22 respectively; to selectively establish a circuit of the'keying means 48 of the transmitter to the proper coding device which are actuated by the control devices 24 and 25 and to selectively establish the circuit of the energizing coils 43, 44 and of the indicating switches 29, 30 and 31, all as will be later described.

It will be noted in the particular circuit shown in the drawings that'the energizing circuit 8, 9 of the transmitter 1 and the energizing circuit of the separate actuating coils 39, 41 and 42' of the connecting switches 20, 21 and 22 are adapted to be connected in par.- allel through the right hand contacts and bridging member of the selecting switches 36, 37 and 38. If we assume that the plug member is inserted in the jack switch 38, this circuit will be as follows: from one side of the source of energy 6 through the left hand contact of the switch 13, conductor 7, actuating coil 42, right hand jacks and bridging member of the selecting switch 38, conductor 9, conductor 10, switch member 11,'conductor 12 and right hand member of the switch 13 back to the opposite side of the source 6.

Likewise a circuit may be traced from oneside of the source 6 through the left hand contact member of switch 13, conductor 7, through conductor 8, primary winding of the transformer 5, conductor 9, conductor 10, switch member 11, conductor 12, right-hand member of the switch 13 back to the opposite side of the source 6. Thus it will be seen that the energizing of the transmitter 1 and of the actuating coils 39, 41 and 42, dependent upon the selecting jack switch into which the plug member has been inserted, is under the control of the switch 11. This switch has an actuating coil 68 whichis adapted to be con-- trolled by electrical contacts of the control devices 24 and 25 through a circuit as follows: from one side of the source 6 through the left-hand contact member of the switch 13, conductor 7, conductor 57, control device 24, conductor 64, actuating coil 68 of the switch 11, conductor 12, right-hand member of the switch 13 to the opposite side of the source 6. This circuit may likewise be traced from conductor 57, through conductor 62, control device 25, to the conductor 64. It will, of course, be understood that separate relays may be provided for connecting the energizing circuits 8, 9 to the source 6 and for connecting the coils 39, 41 and 42 to the source 6 the arrangement shown being preferred for reasons of economy.

Conductor 46 which is connected from the midpoint of the secondary winding 3 of the transformer 5 through the switch member 47 to ground comprises the keying circuit of the transmitter. When the switch 47 isin its closed position, the midpoint of the secondary Winding 3 of the transformer 5 will be at ground potential and proper phase relation for operation of the-transmitter. will be established. When the switch 47 is open these phase relations, and hence operation of the transmitter, are interrupted. Switch 47 is adapted to be actuated by means of a coil 48 which is under control of coding devices associated with conductors 51, 52', 53 and 54,

55, 56 and which are actuated by the control devices 24 and 25, the particular coding device being dependent upon the selecting jack switch 36, 37, 38 into which the plug mem ber'has been placed. For example, if we assume that the plug member has been placed into thejack switch 38, the circuit will be as follows: from one side .of the source of energy 6 through the left-hand contact mem ber of the switch 13, conductor 7, conductor 5'7, through a coding device actuated by control device 24 to conductor 53, conductor 53, through the center contacts, and bridging member 40 of the plug and jack switch 38, conductor 50, conductor 49, actuating coil 48, conductor 12, right-hand member of the switch 13, to the opposite side of the source 6. This circuit will likewise be traced from the conductor 57, through conductor 62, through a coding device actuated by control device 25, to conductor 56, conductor 56 to conductor 53. Thus it may be seen that the keying switch 47 may be actuated in accordance with the coding devices under thecontrol of device 24 or 25 depending upon which is actuated.

The circuit of the energizing coil of the indicator switch members29, 30 and 31 may now be traced. Assuming that the plug member has been inserted into the selecting jack switch 38, the circuit of the actuating coil 45 of the indicating device 28 will be as follows: from one side of the energy source 6, through the left-hand contact member of the switch 13. through conductor 7, conductor 57, conductor 61, through control device 24, contact 66, (Fig. 3) conductor 66, conductor 69, upper half of the actuating coil 45, conductor 70, through the left hand stationary contacts and bridging member of the plug and jack switch 38, conductor 71, conductor 35, conductor 12, right-hand contact member of the switch 13 tothe opposite side of the source 6. Thus upon actuation of the device .24 the upper portion of coil 45 will become energized and the switch 31 will be actuated to the position shown in the drawings, lighting the upper lamp of the device 28, thereby indicating that the transmitter has been keyed to operate the remote switch to which this device corresponds to its closed position. A corresponding circuit may be traced from the conductor 57 through conductor 63, through the control device 25, to conductor 67, conductor 67, conductor 72, through the lower half of the actuating coil 45, to conductor 70. Thus if the control device 25 be actuated the lower portion of the actuating coil 45 will be energized and the switch 31 thrown against its lower stationary contact member, thereby lighting the lower lamp of the indicating device 28 indicating that the remote switch has been operated to its open position.

A better understandin of the control devices 24 and 25 may IIOWTR had from Fig. 3.

These devices are of like construction with the exception that the coding devices associ-.

ated with the control device 24 are adapted to actuate the remote switches to their closed position and those. associated with the device 25 are adapted to actuate corresponding switches to their open position. These devices include two shafts 73 and 74:, upon the former of which is 'mounted an operating handle 77, a contact arm 76and a disc 78, and upon the latter of which is mounted. a disc 79 and a plurality of coding devices 80. The shaft 73 and its attached members are biased to the position shown in the draw ings by the spring 83. Pivotally mounted near the periphery of the disc 79 is a pawl 81 which is adapted to co-act with an indentation 82 in the disc 78 in accordance with a common form of pawl and ratchet arrangement. The operation of the control device shown in Fig. 3 is as follows: When the operating handle 77 is moved in a clockwise direction through substantially 360 degrees the following connections are made to take place. Upon the initialmovement of the arm 76 in a clockwise direction, the contact 64' will fall against the contact 57, it being biased to that position by means not shown, thereby establishing an energizing circuit for the actuating coil 68. When it has been turnedthrough substantially 360 degrees it pushes the contact 66 into engagement with the contact 61, thereby closing the circuit for the actuating coil of one of the indicating devices 26, 27 and 28.

During this portion of the operation the coding devices 80 and the disc 79 have been unoperated due to the pawl and ratchet arrangement 78, 79, 81, 82. At this point the pawl 81 drops into the detent 82 and the handle 77 is released. This handlethen, together with the contact member 76 and the disc 7 8, will be rotated in a counterclockwise direction under influence of the spring 83. At the initiation of this motion the contacts 66 and 61 are immediately separated the circuits of the indicator actuating coils having been established and the indicator switches having been moved to their new positions. The disc 79 is caused to rotate 'in a counterclockwise direction by the pawl and ratchet 81, 82 causing the discs 80 to likewise rotate engaging contact members 51, 52' and 53 and causing them intermittently to energize conductor 57 in accordance with the particular code for which the particular disc, or coding device is adapted to transmit. .When the coding devices 80 have been rotated through a complete revolution the arm 76 will be returned to the position shown in the drawings and the contacts 64: and 57 will be separated. This will deenergize the coil 68 of connecting switch '11 and thereby deenergize the transmitter and disconnect it from the feeder.

It will, of course, be understood that the particular form of device shown in Fi 3 comprises no part of the present invention ut that any suitable device adapted to the purpose may be employed.

The operation of my device shown in Fig. 1 is as follows: If it be assumed that the operator wishes to open a switch located at a remote point, which we will say is actuated by a receiver associated with feeder A- and in response to a particular code, he will first look at the indicating device 26 corresponding to this switch and determine by the fact that the upper lamp of the indicating device is lighted that this switch was last operated to its closed position. He will then insert the plug member .of the plug and jack switches into the selecting jacks 36 and then turn the handle 77 on the control device 25 through substantially 360 degrees in a clockwise direction. Upon the initial movementof the arm 76 in a clockwise direction the contact 64: will be actuated under its bias into engagement with the contact 57 thereby closing a circuit as follows: from one side of the source 6 to the left-hand member of the position closing a circuit as follows from one side of the source 6, through the left-hand member of the switch 13, conductor 7, conductor 8, primary winding of the transformer 5, conductors 9, 10, switch 11, conductor 12, right-hand contact of the switch 13 back to the other side of the source 6. Thus the transmitting circuits will now be energized. Likewise a second circuit will be completed from the left-hand side of the source 6 through the left-hand member of the switch 13, conductor 7, actuating coil 39 of the switch 20, righthand jacks of the selecting switch 36, conductor 9, conductor 10, switch 11, conductor 12, right-hand member of the switch 13 back to the opposite side of the source 6. Actuating coil 39 will now be energized, operating the switch 20 to its closed position, thereby connecting the output circuits of the transmitter to the feeder circuit A. Thus the transmitting circuits are now energized and connected to the proper feeder circuit. lVhen the arm 76 has reached the opposite end of its revolution the contact 66' is pressed into engagement with the contact 61 thereby closing a circuit as follows: from one side of the source 6, through left-hand member of the switch 13, conductor 57, conductor 63, contacts 66 and 61 of the control device 25, (Fig. 3), conductor 67, lower portion of the actuating coil 43 of the indicating device 26, conductor 84, left-hand jacks and bridging member 39 of the plug and jack switch 36, conductor 34, conductor 35, conductor 12, right-hand member of the switch 13 back to the opposite side of the source 6. Thus the lower portion of the actuating core 43 of the indicating device 26 is energized thereby operating the contact member 29 to its lower position and lighting the lower lamp of the indicating device, indicating that the proper code has been transmitted to operate the corresponding switch to its open position. The circuit of the lower lamp of the indicating device 26 has been traced from one side of the source 6 through the left-hand switch member 13, conductor 7, conductor 32, lower lamp of the indicating device 26, lower stationary contact and movable contact 29, con ductor 34, conductor 35, conductor 12, righthand member of the switch 13 to the opposite side of the source 6. Having turned the handle 77 through its complete revolution and the pawl 81 of the disc 79 having fallen into the indentation in the disc 78 the arm is now released by the operator and returns to its initial position under influence of the spring 83. Upon initiation of the return movement the contacts 66 and 61' are separated. This, however, has no effect upon the indicating device 26 since the switch 29 is of the position type and remains in 'the position to which it was last actuated. In returning, the disc 79 together with its shaft 74 and coding devices 80 are rotated in a counterclockwise direction under influence of the spring 83 acting through the pawl and ratchet arrangement 81, 82. Thus a circuit will be made from one side of the source 6 through the left-hand member of the switch 13, conductor 7, conductor 57, contact 51 (Fig. 3), which are actuated by the left hand coding disc 80, conductor 54, conductor 51, center jacks and bridging member 40 of the selecting switch 36, conductor 50, conductor 49, actu-' ating coil 48 of the keying device 47, conductor 12, right-hand member of the switch 13 to the opposite side of the source 6. Thus the coil 48 will be alternately energized and deenergized in accordance with the particular code in response to which the remote switch is actuated. In the particular case shown, the code to which the switch responds is merely a long impulse. The purpose of this will be explained in connection with Figs. 6 and 7. When the arm 76 has returned to its initial position the coding device having been rotated through a complete revolution and the complete code having been transmitted the contacts 57 and 64 are again separated and the connecting devices 68 and 39 are deenergized and their switches operated to the open position. Thus the transmitter is again deenergized and disconnected from the feeder.

The operator may now remove the plug member from the selecting switch contacts 36.

If he desire later to close this switch he will again insert the plug and will similarly operate the control arm 77 of the device 24. Likewise if he desire to operate switches which are actuated by receivers associated with feeder B he will insert the plug member into the selecting switch 37 and then turn the operating handle 77 of the control devices 24 or 25, in accordance with whether it be desired to close or to open the switch respectively. Likewise if he desire to'actu ate a switch associated with feeder 0 he will insert the plug into the selecting switch conin Fig. 1 a separate coding device is provided for each separate feeder and only one coding device, or code wheel, is provided for any feeder. Thus with this arrangement all of the switches which are actuated by receivers associated with a particular feeder are actuated in response to a single code, and those associated with the second feeder are actuated in response to a difierent code and no provision is made for the. selective actuation of diflerent switches associated with a single feeder. In Fig. 4 I have shown a modification of the circuit shown in Fig. 1 adapting it to the selective operation of different switches associated with a particular feeder. In this case let it be assumed that there are associated with feeder A two classes of switches, one which responds to a particular codeand another which responds to a different code, and that there are associated with feeder B switches all of which that there are only two conductors 51 and 52 and 54 and 55 leading to the control devices 24 and 25 indicating that there are but two coding devices. It will also be seen that the right-hand jacks of the selecting switches. 36 and 37 are connected in parallel. Since it is the right-hand jacks by means of which the circuits of the feeder connecting switches 20 and 21 are selected, with this parallel connection the same feeder circuit will be selected upon the insertion of the plug into the jack switch 36 as when the plug is in-.

serted in the jack 37. Thus it will be seen that if the plug member be inserted into the jack switch 36 feeder A will be selected and likewise through the center contacts of this switch, conductors 51 and 54 leading to a particular coding device. Likewise through the left-hand contacts of the selecting switches 36 and conductors 84 and 34 the indicating device 26 will be selected. Thus by insertion of the plug member into the selecting jack 36 connections are established for operating all of the switches on feeder A which respond to a code determined by the coding devices associated with the conductors 51 and 54. If the plug member be inserted into the selectin jacks 37 it will be seen that the same fee er will be connected to the transmitter as when the plugging device was inserted in the selecting jacks 36. However the coding devices associated with conductors 52 and 55 will be selected by the circuit extending through the center contact of the selecting switch. Likewise the indicating device 27 will be selected through av circuit including conductors 85 and 86 and .the left-hand jacks of the selecting switch 37. Thus it will be seen that by inserting the plug into the jack 37 all the connections are established for actuating switches associated with feeder A which are operated in response to a code determined by the codin devices associated with conductors 52 and 55. If the plug member be inserted in the jacks 38 a connection for establishing a circuit to feeder B will be selected includin the right-hand contact and plug member, 0 selecting switch 38, conductor 87 and energizing coil 41 of the connecting switch 21. The center contacts of this switch are connected through conductors 88, conductors 51 and 54 to the code devices which are associated with conductors 51 and 54. Likewise indicating device 28 will be selected through conductors 89-and 90 and left-hand contacts of the selecting switch 38.

In Fig. 5 I have shown modifications of the circuit which are' desirable when all of the switches associated with the various feeders, there being in the case shown three feeders, are operated in response to the same code. It will be seen in this case that only control device is connected through a conductor 51 thence through the center contacts of each of the selecting switches 36, 37' and 38 in parallel to conductor 50 and conductor 49 to the actuating coil of the keying device 47. Otherwise the connections are as shown in Fig. 1. Thus it will be seen that when the plug member is inserted in selecting switch 36, connections for feeder A and indicating device 26 and for the coding device associated with conductor 51 will be established. Likewise if the plug member be inserted in the selecting switch 37 connections will be established for feeder B, indicating device 27 and the same coding device and likewise if the plug switch is inserted in the jack 38 connections for feeder C, indicator 28 and the same coding device will be established.

Thus it will be seen that as many indicating devices and cooling devices are provided for each feeder as there are receivers associated with that feeder which respond to different codes.

Each of the circuits shown in Figs. 1, 4 and 5 are provided with means whereby the circuits may be controlled manually and independently of the control devices 24 and 25. This means comprises the switch 142 which when closed is adapted to retain the keying switch 47 and the connecting switch 11 in their closed position. Likewise acting through the right-hand plug and jack members of the selecting switches 36, 37 and 38 it will retain the selected connecting switch 20, 21, 22 in. its closed position. The circuits of the energizing coils of these switches when switch 142 is closed are as follows: leading from one side of the source 6 through the left-hand member of switch 13, conductors 7, 8, 143, switch 142, conductor 50, conductor 49, energizing coil 48, conductor 12, right-hand member of switch 13 to the other side of the source 6'. Thus the coil 48 will be energized and the switch 47 held closed. Likewise the circuit of coil 68 extends through conductors 7, 8, 143, switch 142, conductor 64, coil 68 and conductor 12. The circuilt of coils 39, 41 and 42 will be as pre- VlOllS traced. Thus when the switch 142- is in 1ts closed position the transmitter is energized and connected to a feeder A, B, O, dependent upon the switch 36, 37, 38 into which the plug has been inserted. Keying may now be effected by any desirable means as by a hand operated switch in conductor 46.

In Fig. 6 I have shown the preferred receiving circuit of my .system. In this figure, I have indicated an electron discharge device having an anode 93, cathode 94 and grid 95. The cathode 94 is adapted to be heated from a secondary winding 96 of the transformer 97 and the anode circuit is adapted to be energized through a circuit leading from the cathode 94 through conductor 98, secondary winding 99 of the transformer 97, energizing coil of the relay 100, conductor 101 and anode 93. Likewise the grid circuit is adapted to be energized through a circuit including the cathode 94, conductor 98, secondary winding 103 of transformer 97, resistance 104, secondary winding 105 of the transformer 106 to the grid 95. The primary Winding of the transformer 97 is connected to a source of alternating current potential 107 through conductors 108, 109, primary winding of the transformer 97, conductors 110, 111, 112. The primary winding of the input transformer 106 is connected to the feeder circuit through the coupling condensers 114, drain reactors 115, strain reactors 113 and arresters 141 being provided for protective purposes. It will be seen that the grid and anode of the electron discharge device 92 are connected to opposite points on the secondary windings of the transformer 97 to the cathode connection 98. Hence voltages impressed upon the grid circuit will be substantially opposite in phase from those impressed upon the plate circuit. Hence by properly proportioning the turns in windings 103 and 99 I am enabled to cause the device to operate as a biased detector during the portion of the cycle in which the anode is at a positive potential with respect to the cathode and the grid is at a negative potential with respect to the cathode.

Thus, if during this half cycle carrier current voltages are impressed upon the grid circuit through the transformer 106, a detecting current corresponding in intensity to the intensities of the carrier will flow in the anode circuit. This current will energize the actuating coil of the relay 100 which for purposes of sensitivity may be of the polarized type, and charge the condenser 140. During the opposite half cycle no current will flow in the anode circuit due to the fact that this is now at a negative potential with respect to the cathode .but the armature of the relay 100 will remain in its closed position due to the discharge of the condenser 140 through the windings of the relay.

I have found that due to the effect of apparatus connected in the grid and anode circuits, such as the winding 105, condenser 140 and the relay 100, that the voltages impressed upon the grid and the plate may deviate from the 180 degree relation and that the efiiciency of the detector maybe greatly diminished thereby. I have also found that due to current flowing in the grid circuit of the detector during the inoperative half cycle energy is stored in the inductance of the input circuit which tends to hold the grid positive after the plate has become posi-, tive. Consequently a short rush of current in the plate circuit will take place at the beginning of each operative half cycle independently of the received carrier. The effect of this current is to charge the condenser 140 which later discharges through the relay, adding its current to thatwhich flows responsively to the carrier impulses and therebynecessitating an adjustment of the relay such that it is less sensitive to the received carrier, and decreasing the overall efficiency of the detector. To minimize this effect and to correct for the above mentioned phase displacement the resistance 101 is inserted in the grid circuit of the detector sufficient in magnitude to reduce the grid current substantially to zero.

The transformer 106 is so designed as to have an inherent resonant point at the frequency of the carrier which is to be employed. Thus at this frequency the voltage across the winding 105 will be many times greater than that existing at any other frequency.

This secondary voltage willvary with frequency in accordance with a comparatively sharp resonant curve of the transformer. By this means I am enabled to dispense with the use of external capacity or'other external tuning means in the grid circuit of the detector. This is a particularly important feature in that it facilitates the installation of the receiver by linemen or other persons not particularly skilled in high frequency apparatus. The inherent resonant curve of this transformer however will not be so sharp but that frequencies within the range caused by commercial variations in the constants of the oscillatory circuit of the transmitter will produce voltages upon the secondary circuit which will permit of satisfactory operation of the device. If desired a fixed capacitor may be connected across the windings of the transformer. This transformer is also of the high impedance type such that the impedance looking into the circuit, inclusive of the coupling condensers, drain reactors 115 etc. is substantially above any characteristic impedance of the feeder with which the circuit is associated. By these means it is possible to reduce the reflection losses and to diminish the effect of the apparatus upon the carrier energy level of the feeder. By this means also theeffect of changing line impedances upon the tuning of the receiver is greatly reduced. This receiver is described and claimed in my Patent No. 1,755,091 issued April 15, 1930.

In order to adapt this receiver to the .operation of switches such as the control switch 116, I provide in connection therewith a relay such as is shown in Fig. 7. This relay is of the form of-conducting members 124 and 125 projecting within the opposite ends of the tube. These projections are connected to conductors 126 and 127 leading to the energizing circuit of the switch which is to be operated. The mercury tube 123 is by any suitable means, such as a block of wood or other material 128, mounted upon a shaft 129. Securely attached to this shaft is an element 130 having at its upper end a projecting member 131 and at its lower end a projecting member 132. Also mounted upon the shaft 129 is an element 133 which is freely rotatable thereon. This element is biased to the vertical position by gravity and has at its upper extremity, which extends above the projecting member 131 of the element 130, a projecting member 1344 This member projects within the path of the element 122. On the lower side of the disc 119 is a projecting member 135 which may be located at any suitable angular distance from the member 122.

The operation of this relay may now be explained. In the position of the mercury tube shown in the drawings the mercury is in the left end of the tube and connection between the members 124 and 125 is broken. If we assume that alternating current be applied to the coil 117 for a definite interval the disc'118 will rotate causing the disc 119, shaft 121 and the element 122 to rotate in the direction of the arrow shown on disc 119. The member 122 will engage the projecting member 134 on the member 133 causing it to bear against the member 131 of the element 130.

Thus the element 130 together with the shaft 129, block 128 and the mercury tube 123 will be caused to rotate in a clockwise direction until the mercury in the tube 123 runs to the opposite end of the tube under gravity and closes an electrical circuit between the contacts 124 and 125. The membar 132 will be carried to the left into the path of the member 135. If the circuit of the coil 117 is now broken and the co l deenergized, the mercury tube 123 will remain in the position to which it has been actuated under the influence of gravity. The arm 122 will return to its initial position under the influence of thebiasing members 136. In returning it will engage the projecting member 134 causing it to rotate upon the shaft 129. This, however, will have no effect upon the tube 123 due to the fact that the member 123 is free to rotate upon the shaft 129 and to the fact that the upper extremity of the member 133 is at the left or counterclockwise side of the projecting member 131 of the element 130. If now the coil 117 be energized for a longer interval than before member 122 will be rotated engaging the member 134 which freely rotates upon its shaft but which does not now engage the member 131 due to the fact that this member was previously operated to its opposite extreme position. The member 135 however will engage the projecting member 132 caus-' ing counterclockwise motion of the element 130 and of the mercury tube 123. This in turn interrupts the circuit of the electrical contacts 124 and 125.

Thus it is seen that in response to energization of the coil 117 for a certain interval the mercury tube 123 may be so operated as to close the circuit between the conducting members 124 and 125, whereas in response to energization of the coil 117 for a certain longer interval the mercury tube 123 may be so operated as to break the electrical con.- nections between the conducting members 124 and 125.

A coding device for the purpose of transmitting a code consisting simply of a long impulse has been shown at the left of Fig. 3. If this device be actuated by control device 24 then the relay shown in Fig. 7 will be so adjusted that a circuit between conducting members 124 and 125 will be established in response to this long impulse. A similar device adapted to transmit an impulse of longer duration will be actuated by control device 25 for the purpose of opening the circuit between conducting members 124 and 125.

The circuit by means of which the relay shown in Fig. 7 is caused to operate responsively to carrier impulse transmitted over the feeders and which are detected by the discharge device is shown in Fig. 6. When the carrier impressed upon the receiving apparatus is sufficient to actuate the armature of the relay 100 to the closed position a circuit will be established from one side of the alternating current source 107 through conductor 108, conductor 109, energizing winding 117, conductor 137, armature and stationary contact member of the relay 100, conductors 110, 111 and 112 back to the other side of the source 107. Thus the relay will be actuated to close the circuit between the conductors 126 and 127 through conducting members 124 and 125 and to energize the coil 138 of the switch 115 116 through a circuit leading from one side of the source 107 through conductor 112, conductor 111, conductor 139, energizing winding 138 of the switch 116, conductor 127, conducting member 125, mercury within the 120 tube 123, conducting member 124,.conductor 126,'conductor 108 back to the source 107. The switch 144 is connected in shunt with the contacts of relay 100 to provide means I whereby the local operator may operate the 125 relay 117.

The receiver shown is but one of many types which may be employed. lVhile I have shown this receiver in connection with a particular relay it will of course be under- 130 stood that it may be used to energize any of the usual selector relays such, for example, as those shown in Patent No. 1,343,256, Field, and No. 1,148,319, Hill for selectively operating remote switches in response to desired codes. It will of course be understood that the means whereby the code impulses are supplied to the selector, including the form of code device 80 used in the transmitter, will be designed in accordance with the type of selector used on any feeder, the coding devices indicated being shown merely for the purpose of indicating the presence of a plurality of coding devices each of which may be of any desired form.

WVhile I have illustrated and described a particular embodiment of my invention, I do not wish to be limited to the particular circuit arrangement shown, as it will be apparent that many modifications may be made in the circuit arrangement and in the apparatus employed without departing from the scope of my invention as set forth in the' appended claims.

What I claim as new and desire to secure by Letters Patent of the United Statesis:

1. In a system for selective performance of remote functions, the combination with a plurality of circuits, of a transmitter, means individual to each circuit for connecting said transmitter to the respective circuit, selective switching means, and a control means operable through said switching means for actuating said connecting means to connect said transmitter to a selected circuit, for keying said transmitter through said selective switching means in accordance with the func-' tion to be performed and for actuating sai'd connecting means to disconnect said transmitter from said circuit after said keying has been effected.

2. In a system for selective performance of remote functions, the combination with a plurality of circuits, of a transmitter having impulsing means, means for connecting said transmitter to said circuits, a plurality of coding means each corresponding to a function to be performed, switching means for selec tively establishing an energizing circuit for said circuitconnecting means and for selectively connecting said impulsing means to said coding means and a control means operable through said switching means to actuate said circuit connecting means to connect said transmitter to a selected circuit, to actuate said impulsing means through said switching means in accordance with a selected one of said coding means and to actuate said connecting means to disconnect said transmitter from said circuit.

3. In a system for selective performance of remote functions, the combination with a plurality of circuits, a transmitter having a keying circuit, means for connecting said transmitter to said circuits, a plurality of coding means corresponding to functions to be performed, a common switching means for selectively establishing an energizing circuit for said circuit connecting means and for selectively connecting said keying circuit to said coding means whereby said transmitter is keyed through said switching means in accordance with a selected coding means and a control means adapted in response to a single operation of the operator to actuate said coding means and operable I through said switching means to actuate said circuit connecting means to connect said transmitter to a selected circuit, and to actuate said circuit connecting means to disconnect said transmitter from said circuit.

4. In a system for selective performance of remote functions, the combination with a plurality of circuits, of a carrier current transmitter, a source of energy, means for connecting said transmitter to said source of energy, means associated with each circuit for connecting said transmitter to the respective circuit, selective switching means, and a control means for actuating said connecting means to connect said transmitter to said source of energy, said control means being operable through said switching means to connect said transmitter to a selected circuit, for ke ing said transmitter through said switc ing means in accordance with the function to be performed and for actuating said connecting means to disconnect said transmitter from said source of energy and said circuit after said keying has been eflected.

5. In a system for selective performance of remote functions, the combination with a plurality of circuits, of a transmitter, a source of energy, means for connecting said transmitter to said source of energy and to said circuits, a plurality of coding means corresponding to functions to be performed, switching means for selectively establishing connections 7 to said coding means and to said feeder connecting means, and control means for actuating said connecting means to connect said transmitter to said source of energy, said control means being operable through said switching means to connect said transmitter to a selected circuit for actuating said-coding means and for actuating said connecting means to disconnect said transmitter from. I

said source of energy and said circuits after said coding means has been actuated.

6. In a remote control system, the combination of a plurality of circuits, a transmitter, keying means therefor, a source of energy, means associated with each circuit for connecting the transmitter to the respective circuit, means for connecting said transmitter to said source of energy, a plurality of coding devices, selective switching means arranged to connect said keying means to a selected coding device and to establish connections to a selected one of said circuit connecting means, and means responsive to a single operation of the operator to actuate said connecting means to connect said transmitter to said source of energy, to operate said coding devices whereby said transmitter is keyed through said switching means, and operable through said switching means to actuate said circuit connecting means to connect said transmitter to the selected circuit before said coding device is operated and subsequently to disconnect said transmitter from said circuit.

7. In a remote control system, the combination of a plurality of circuits, a transmitter having a keying circuit, a source of energy, means for energizing said transmitter, means associated with each circuit for connecting the transmitter to the respective circuit, a plurality of coding devices, switching means for selectively establishing connections to said circuit connecting means and for selectively connecting said keying circuit to said coding devices whereby when said coding device is operated said transmitter is keyed through said switching means, and a common control means for actuating said energizing means and said selected coding device, said common control means being operable through said switching means to actuate the selected circuit connecting means to connect said transmitter to a selected circuit before 0 eration of the coding devices and for therea ter actuating said circuit connecting means to disconnect the transmitter from the selected feeder and to actuate said energizing means to deenergize the transmitter.

. 8. In a remote control system, the combina- 'tion of a circuit, a high frequency vacuum tube transmitter, a source of energy, indicating means, selective switching means, and a common control means operable through said selective switching means to key said transmitter inaccordance with a remote function to be performed, and to actuate said indicating means through said selective switching means in accordance with said function, and means responsive to said common control means for energizing said transmitter during said keying thereof and for thereafter deenergizing sald transmitter.

9. In a system for selective performance of a plurality of remote functions, the combination with a circuit extending to a remote point, of a carrier current transmitter associated with said circuit and keying means therefor, a source of energy, means for connecting said transmitter to said source of energy, a plurality of coding means, switching means for selectively connecting said keying means to said coding means according to the function to be performed and a single control means for actuating said connecting means to connect said transmitter to said energy source, for actuating said coding means whereby said keying means is operated through said switching means in accordance with a desired code and for actuating said connecting means to disconnect said transmitter from said energy source after said coding means has been actuated.

10. In a system for selective performance of remote functions, the combination with a plurality of circuits, of a high frequency transmitter, a source of energy, coding and indicating means corresponding to functions to be performed, means for connecting said transmitter to said source of energy and to said circuits, switching means for selectively establishing connections to said coding, indicating and circuit connecting means, and a single control means for actuating said connecting means to connect said transmitter to said source of energy, and for actuating said coding means whereby said transmitter is keyed through said switching means in accordance with a selected code, said single control means being operable through said switching means both to operate said circuit connecting means to connect the transmitter to a selected circuit and to operate said indicating means in accordance with the code transmitted and for thereafter actuating said connecting means to disconnect said transmitter from said source of energy and selected circuit. 7

11. In a remote control system, the combination with a plurality of circuits, of a high frequency transmitter and keying means therefor, a control system for said transmitter including means for connecting said transmitter to said feeders, a source of energy, means for connecting said transmitter to said source of energ selective switching means, a control device operable through said selective switching means to actuate said connecting means to connect said transmitter to the selected circuit to actuate said keying means in accordance with the code to be transmitted and to disconnect said transmitter from said circuit after said keying means has been actuated and means controlled by said control-device and switching means for indicating the circuit selected and the code transmitted.

12. In a system for selective performance of remote functions, the combination with a plurality of circuits, of a high frequency transmitter having a keying circuit, a source of energy, means for connecting said transmitter to said source of energy, means for connecting said transmitter to said circuits, a plurality of coding and indicating means corresponding to functions to be performed, a common means for selectively establishing an energizing circuit for said circuit connecting means, for selectively connecting said keying circuit to said coding means and for selectively establishing a circuit to said indicating means, and control means for actuating said connecting means to connect said transmitter to said energy source and to the selected circuit, for actuating said indicating means, for actuating said coding devices and for actuating said connecting means to disconnect said transmitter from said energy source and from said circuit.

13. In a system for selective performance of remote functions, the combination with a plurality of circuits, of a high frequency transmitter having a keying circuit, a source of energy, means for connecting said transmitter to said source of energy, a plurality of coding and indicating means corresponding to functions to be performed, common switching means for selectively connecting said keying circuit to said coding means and for selectively establishing a circuit for said indicating means, and control means for actuating said coding means whereb said transmitter is keyed through said swltching means, said control means being operable through said switching means to actuate said indicating means, and means responsive to said control means for actuating said connecting means to connect the transmitter to said source of energy while said coding means is actuated and subsequently to disconnect said transmitter from said source of energy.

-coding means and for selectively establishing an energizing circuit for said indicating means, and control means operable through said switching means for actuating said connecting means to connect said transmitter to the selected feeder, for actuating said coding devices whereby the transmitter is keyed through said switching means in accordance with a selected code and for actuating said connecting means to disconnect said transmitter from said circuit after the coding means has been actuated.

15. In combination, a transmitter having a keying circuit, a plurality of circuits, a plurality of coding devices, means associated with each circuit for connecting the output from said transmitter to the respective circuit, selective switching means for connecting said keying circuit to a desired coding device and for establishing connections to said circuit connecting means, and a common means for actuating said coding device, whereby said transmitter is keyed through said selective switching means, said common means being operable through said switching means to actuate said distribution circuit connecting means.

In witness whereof, I have hereunto set my hand this 28th day of May, 1927.

HUGH E. ALLEN. 

